One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,9)(4,12)(5,7)(6,10)(8,14)(11,16)(13,15)(17,18)(19,27)(20,31)(21,32)(22,25)(23,28)(24,30)(26,29) involution — undirected(1,3,5,11)(2,6,7,15)(4,13,14,10)(8,16,12,9)(17,19,23,22)(18,24,28,31)(20,29,30,21)(25,32,27,26)(1,2)(3,6)(4,8)(5,7)(9,10)(11,15)(12,14)(13,16)(18,25)(19,22)(21,29)(24,26)(27,28)(31,32) involution — undirected(2,7)(6,15)(8,12)(9,16)(17,20,23,30)(18,24,28,31)(19,29,22,21)(25,26,27,32)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.