Change Photo Sort to Event, not Faces

Ok, so I'm probably missing something really obvious, and I promise I tried to search for an answer first, but this has me completely stumped...

After adding a heap of Face tags to my pics in iPhoto, I now find that my iPhone is sorting all my photos by Faces and I can't find a way to switch it back to Events (or any other kind of album, really).

It was all fine until I decided to import my whole library of photos onto the phone, but surely I can keep all the pics there without sacrificing a bit of organisation...?