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