The incident occurred during the first-half of the match in Cadiz, with Diakhaby visibly upset after an altercation with Cadiz defender Juan Cala.
Cala and Diakhaby exchanged words and Valencia players eventually grouped together and left the field.
They later returned and Valencia said in a statement the team decided to return to the field after a request by Diakhaby.
“The team have held a meeting and decided to continue the game, in order to fight for the honor of the club, but denounce racism of any kind,” it said in its Twitter account in English.
“The player, who had received a racial insult, requested that his teammates return to the pitch.”
“Valencia said it offered its “complete backing” to Diakhaby. “WE SUPPORT YOU MOUCTAR,” it wrote.