You may also like some Paul Dukas, a contemporary and friend of Debussy, who was also Messiean's composition teacher. His famous work is "The Sorcerer's Apprentice", which Stravinsky Quoted in his early work "Fireworks". Dukas also wrote a symphony, and a ballet, "La Peri". You don't get much more colorful then his music.
Also, as far as colorful music, check out Rimsky-Korsakov. He is Stravinsky's teacher. In Particular, check out his "Russian Easter Overture". Also another Russian, who was a big influence on Debussy is Modest Mussorgsky. Debussy liked his opera "Boris Godunov". Mussorgsky was very original, but not as colorful orchestral-ly. Ravel also orchestrated his "Pictures at an Exhibition".
I know these people are a little earlier time was then what you are looking for, but musically, I think you will like them. You can think of it like checking out Monk's influences and discovering Duke Ellington, and checking out Dukes influences and discovering Willie the Lion Smith. Etc..
I hope this is helpful! All of the people listed in other's posts are also fantastic.