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