Shuffling all of your songs is a bit of a mystery in the new Apple Music app on iOS. Wired has found a really quick short cut to allow you to shuffle every song in your library. All you have to do is ask Siri: “Shuffle All My Music”
If you haven’t been using Siri much for music, there are some additional commands you can use I found over at iMore
iMore has 9 other tips to using Siri with Apple Music you can check out here.