Get her a Longchamp. Not the standard pliage but a overnight bag/holdall in cavass because it's difficult to judge a 40-year-old tastes, LOL and she will definitely use the holdall to the gym, weekend break, etc.
Maybe something by Dooney and Bourke... the leather collection? They have some really nice leather bags... try the all-weather leather collection or the Alto line.. very mature, very nice
longchamp is a good idea. they have leather bags as well, some of them are very nice, not my style but they are definitely classic and tasteful and i can imagine someone appreciating one as a gift.