The coloring page offers an interesting subject matter: Ratatouille's villainous head chef, Skinner. He has a confident, almost arrogant expression on his face, standing with a spoon and whisk in his hands. Above him is a stove with a pot that is full of colors, offering a great opportunity for adding vibrancy to the page.
I would color Skinner in a warm, yellowish brown palette, using a darker shade for parts like his clothes and muzzle to bring him out against the rest of the page. The pot on the stove could be a rainbow of colors to bring it to life, from bright oranges and yellows to deep reds and purples. The vegetables can provide even more colors, from light greens to dark browns and vivid blues. All of these colors when put together will help bring the character and scene altogether in a vibrant artwork.