When you start getting to really know angels, that image of flowing white robes and gold halo goes right out the window. They are all so wonderfully unique, with their own tastes and personalities you really can't give them all the same look. Angels appears different for every person, mostly because we can't really understand their true forms or nature. So our minds fill in the blanks by giving them appearances that we can grasp and that relays something about them to us using the language of metaphor. Most non-physical beings work this way, and it helps human understand and accept them.
I keep a sketchbook of drawings I have done of the angels I have met. They are all as different as we are and I hope people can learn to appreciate that.