The first thing to remember is that there are many variations depending on the location, religion or sect. The best you can do is pick a set and stick to it. This does not invalidate any other set.

go shiki — Five colors. Derived from Buddhism. You will frequently see these on flags drapped across the temple entrance, or on nobori* set along the path leading to the entrance.

* A long, narrow banner attached to a pole on one side and a horizontal rod along the top.

• aka — red: south, scarlet (compound color), summer, fire, zeal
  alternately — amida nyorai, west, water
• kiiro — yellow: center, brown (compound color), earth, memory
  alternately — water
  alternately — hôshô nyorai, south, fire
• ao — blue (green): east, green (compound color), spring, wood, meditation
  alternately — ao — blue: ashuku nyorai, east, earth
  alternately — midori — green: fukûjôju nyorai, north, air
• shiro — white: west, crimson (compound color), autumn, wind, faith
  alternately — dainichi nyorai, center, mind, space
• kuro — black: north, purple (compound color), winter, water, wisdom
  alternately — space, void

Small paper mache daruma come in many colors. These are some of the meanings associated with those colors. This list is by no means definitive or exhaustive.

• aka — red: best of luck, good fortune.
• momo iro — peach: love, romance, passion.
• PINKU — pink: safe delivery, good relations
• daidai iro — orange: children, protection against disaster, academic success, prosperity
• kiiro — yellow: financial good fortune, good fortune.
• midori — green: physical health, development of talent and skill
• ao — blue: career success, success in school, development of the intellect.
• murasaki — purple: personal development, health, longevity
• gin — silver: promotes self-awareness, self-development, easy delivery
• kin — gold: glory, wealth, prosperity
• shiro — white: goal attainment, purity, balance
• kuro — black: success in business ventures, protection against evil spirits