Thankfully, the days of cookie-cutter houses built quickly to exactly the same design are on their way out. Even in places where the homes are all based on the same floor plan, individual home owners add and change things to suit themselves. One of the easiest things to change in any home is the color of the exterior walls.
Passive solar homes can be any color, just like normal homes, but they lose a major advantage if they aren't painted to suit the climate. Light-colored homes reflect the sun's light, reducing the amount of heat retained in the walls and, therefore, lowering summer cooling loads. Dark-colored homes absorb more heat from the sun, thus increasing the amount of passive warmth transferred to the interior in winter.
As an additional note, light-colored walls extend the life of siding, especially on the sides that face the sun (south, east, and west).
Funnily enough, roof color has little effect on heat absorption. It doesn't really matter whether you have a white, black, or red roof – your home won't notice a significant difference. It still makes sense to opt for light colors in hot climates, though, for whatever minor benefit you can get!
Roofing material has a far more profound effect on heat gain and retention. Tile roofs are great at reducing heat gain (especially Spanish tile) because they have a gap between the tiles and the decking. The same goes for metal roofing on sleepers. Placing rigid foam insulation on the decking further retards heat gain (and aids heat retention in winter).