Think of how you apply the meaning of color day to day. Color is something that surrounds us and has since the beginning of time. Color effects our perception and even our mood. Color also holds unfathomable depths of symbolism.
One thing that we apply color symbolism to but should not, is actually magic itself. The two most common forms of "color magic" are the ideas of "white" and "black" magic. White magic generally considered good is the opposite of black magic, which is of course bad. However, the symbolism usually applied to these colors does NOT apply here because the good or evil of magic is determined by the individual, general purpose, and final outcome. In either form of these two magics, the final outcome can have unforseen results that go against the general symbolism of whichever type you have used.
There still remains plenty of room for color symbolism in magic, despite its common misuse. The planets in the Milky Way Galaxy show one use of proper color symbolism. Proper color symbolism is used when a color, though it may have various meanings, is generally accecpted by the majority (EXAMPLE: Color= Red- Life bc of our blood, anger, and passion). Probably that largest factor in proper use is that whatever purpose you are using a color for is set in its meaning for your goal and the meaning cannot become the opposite bc oif the purpose of your color changes, then so does your goal.
In conclusion, I actually managed to only scratch the surface of the different ideas behind color. I would actually suggest to further research colors independantly. As you further your understanding in this area, do not forget what you have read here.