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