A furious Diakhaby walked off the field after being involved in a heated exchange with Cala and claimed the Spanish player had used a racist slur towards him in the first half of Valencia's game in Cadiz three weeks ago.
Three goals in 10 minutes towards the end of the first half helped Madrid go top of the table on head-to-head, above Atletico Madrid, who play at home to Huesca on Thursday.
LaLiga: No evidence to support Mouctar Diakhaby’s allegation of getting racially abused by Juan Cala, says league
The league said it has analysed all the available video and audio of conversations between the two players, including hiring a company specialised in lip reading, but found no proof of racially abusive language.
Valencia reacted angrily to Cala's press conference, releasing a statement later on Tuesday entitled: "Juan Cala, we don't believe you."
LaLiga investigating Valencia's claim that Mouctar Diakhaby was racially abused, Javier Tebas confirms
"We are already carrying out an internal investigation with the videos and images of the game we have to clarify what happened," said Tebas.
LaLiga: Cadiz's Juan Cala, accused of racial abuse of Mouctar Diakhaby, wants to be presumed innocent
“Apparently the presumption of innocence doesn’t exist in this country,” Cadiz's Juan Cala told a Spanish television channel before stating that he will soon share his version of what happened.
Diakhaby had been involved in a heated exchange with Cadiz's Juan Cala before indicating to the referee David Medie Jimenez that he was leaving the field.
LaLiga: Atletico Madrid bounce back with 2-0 win over Villarreal; Real Valladolid draw 1-1 at Celta Vigo
An own goal from Alfonso Pedraza and Joao Felix's powerful strike gave Atletico a precious win after a wobble which had allowed Barcelona and Real Madrid to gain ground in the title race.
Barcelona had won their previous seven games and another victory would have put them back within touching distance of Atletico, even if LaLiga's leaders have played one game fewer.
LaLiga: Lionel Messi stars in Barcelona's 3-2 comeback win over Real Betis; Real Sociedad ease past Cadiz
Messi showed why Barcelona agreed to keep him an extremely rich man when on Sunday he acted as Ronald Koeman’s super-sub, scoring one goal and setting up another to help Barcelona earn a 3-2 win at Real Betis.
LaLiga: Luis Suarez brace takes Atletico Madrid 10 points clear; Barcelona level with Real Madrid in second
Antoine Griezmann also scored for Barcelona, who won their fifth in a row in the league and moved into second place for the first time this season.
European football matchday: Tough test for Liverpool against Hammers; Atletico Madrid look to extend lead
Liverpool start in fourth place and two points ahead of West Ham, who have won their last four games.
Valencia ended an eight-game winless streak and moved further from the relegation zone with a 1-0 win at Valladolid in the Spanish league on Sunday.
Forward Maxi Gomez equalized late for Valencia to draw with Cadiz 1-1 at home in the Spanish league.
Liverpool heads to Southampton atop the Premier League in its title defense but now only due to having a better goal difference than Manchester United.
LaLiga: Lionel Messi-less Barcelona held 1-1 by Eibar; Jose Morales' brace helps Levante edge Real Betis
With Lionel Messi nursing his ankle in the stands, Barcelona fell further behind in the Spanish league on Tuesday after ceding their first-ever point to Eibar at Camp Nou.
Cadiz were coming off beating Barcelona 2-1 at home but started badly and by halftime were down 4-0.
LaLiga: Real Sociedad extend lead at top after win over Cadiz; Valencia play out draw against Alaves
Real Sociedad remained in good form after the international break with a 1-0 win over Cádiz on Sunday for their sixth straight league victory and a three-point lead at the top of the standings.
What to watch in European football today: Leicester hoping to spoil Liverpool's record, Milan to test unbeaten run against Napoli
Liverpool have not lost their last 63 league games at home. That matches a club record set in December 1980 which was ended by a defeat to Leicester.
Zidane said Sergio Ramos will be available to face Barcelona after recovering from the knee injury that kept him out of the loss to Shakhtar on Wednesday.