One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10)(11,13)(12,14)(15,16)(17,18)(19,23)(20,31)(21,24)(22,27)(25,30)(26,29)(28,32) involution — undirected(2,5)(6,8)(9,11)(10,13)(12,15)(14,16)(17,19,22,28)(18,23,27,32)(20,21,30,29)(24,25,26,31)(11,15)(13,16)(18,24)(19,28)(21,29)(23,31)(25,32)(26,27) involution — undirected(10,14)(13,16)(17,20,22,30)(18,25,27,31)(19,29,28,21)(23,24,32,26)(1,3,4,7)(2,6,5,8)(19,28)(20,30)(23,32)(25,31)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.