There are many different colours of cape, some you can buy, some you have to make. Here is a step by step guid on dying capes.
Red dye-3 red berries
Blue dye- 2 wooden leaves
Yellow dye- 2 onions
Purple cape- Blue+Red dye
Green cape- Yellow+Blue dye
Yellow cape-Yellow dye
Orange cape-Yellow+Red dye
Red cape-Red dye
Black cape-Buy in fine clothing store
White cape- (new*) Buy in lengend guild (members onley)