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