A diverse group is made up of people or things that are very different from each other. If your class mixes kids from all over the world, you could call it a diverse.
The adjective diversified has the same meaning, and a near synonym is varied. An earlier spelling of the English adjective was divers, and the final –e was probably added by association with words such as traverse and converse. The word divers is still in use in the sense "more than one, several, various:" divers methods and styles.