Some common colors for robes and their meanings are as follows:
Silver: Connects with the Goddess.
Gold: Connects with the God..
Green: Connects with the energy of the earth..
Blue: Connects with the energy of water..
Yellow: Connects with the energy of air..
Red: Connects with the energy of fire..
Pink: Connects with the energy of the heart..
From:
Natural Magick : Inside the Well-Stocked Witch's
Cupboard by Sally
Dubats