Using a canvas object to display the selected color would be rather cumbersome. Either you have a premade list/dictionary of the selections and colors to fill the canvas with, or you use the canvas that covers the whole area to take a snapshot, look up the color at the coordinates that were clicked, and then fill the display area with that color.
Personally I'd just use a sprite object with all the colors as animation frames, and set it the right frame when selecting a color.