We don't have the models name, but the photographer is Carmine Schiavone, who was a very famous photographer of many models. I'm quite sure Joan Holloway would have been a fan!
When I saw this cover I stopped in my tracks...it's Joan Holloway! Well, it isn't, but wow, she's a dead ringer. Actually this Vogue Pattern Book is from the spring of 1960, a few years before Mad Men, but I figure Joan had a few things in her closet. Like this Vogue pattern 9950, "A dress with the newest silhouette this spring - the cornucopia sleeve. Black-and-white silk surah by Maxwell; Midtown patent belt. Marvella earrings."