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