What color are the directional capacitors?

They can be many different colors, shapes and sizes. To identify whether a capacitor is directional or not, you must look at the markings on it - if it is directional, it will have a little +, and possibly a - to denote directionality (some only have the + I believe due to size).

In general, electrolytic capacitors are normally directionalized. These are the capacitors that resemble batteries in shape, and usually have an 'X' on the bottom (this creates a weak point in the casing; if the capacitor overheats for whatever reason - overvoltaging, or revers polarizing- the 'X' will fail first).