There is no official Buddhist color for all Buddhists. Monks and Nuns wear color associated with their specific lineage. Also, the sturcutre of Buddhism is very diffuse.

Unlike many Christian churches, in which there is a hierarchy of responsibility and control, Buddhism has no overall structure or central church. There are different Buddhist traditions, called lineages, such as Tibetan Buddhism, or Theravada Buddhism, Zen Buddhism, etc, but each lineage might or might not have a Lineage Master (like the Dalai Lama, who is the Lineage Master for the Gelug tradition of Tibetan Buddhism). To explain this you need to understand how Buddhism is taught.

Buddhist masters are monks who have learned the teachings sufficiently and has the ability to speak authoritatively about the teachings. They have received permission to do this from their master. This permission is called being given transmission. The monk could then go to another area, open a monastery and then teach others. If one of his monks then learns the teachings sufficiently, the new master could give transmission to his student, and the cycle continues. Please note that learning the teachings of the Buddha is not memorization, these masters must completely understand and be able to explain the teachings in their own words.