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