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