Rachel is a woman working in a man's world on a completely different level than Joan or Peggy. She's at the top and determined to stay there, well, at least until she "falls in love." But in the mean time, in no way does that mean she sacrifices the fact that she is an extremely attractive woman. Her brains and beauty come as a package deal. That was clear to me the moment I saw her in her purple Chanel suit and double-strand of pearls. No sex-less gray suit and glasses for her.
The Mai Tai dress with matching stole, lipstick, and nail polish. I wonder if Menken's has an in-store beauty parlor? At this point she was under the impression that Don was single.
It's a far cry from the outfit Rachel chose to wear when she greeted Don for a tour of her empire, a few episodes earlier. I was pretty disappointed with this outfit because it caused her to blend in with the surroundings. However, I was pleasantly surprised to see that it was shot through with metallic (maybe Lurex?) gold threads. It caught the light every now and then and looked expensive.
How about that extremely bold color and that hat? What else could scream "I am a woman" louder than that ensemble? Fortunately, it also happens to be what she is wearing when she bumps into Don, now that she knows he is married. Therefore, you can say it also works as a "Look, lust, but don't touch" outfit.
The "Chanel" woman in you can be found on vintage pattern sites with search terms like JackieO and wiggledress.
Vogue 5766, Advance 9516, Vogue 5102, Vogue 4206, and
Vogue 5548 (just the last look)