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)(17,25)(19,27)(20,24)(22,28)(23,26) involution — undirected(1,2)(3,4)(5,7,8,12)(6,9,10,11)(13,14,18,16)(15,19,23,22)(17,20,25,24)(21,27,26,28)(2,4)(13,15,18,23)(14,19,16,22)(17,26,25,21)(20,28,24,27)(6,10)(9,11)(13,16,18,14)(15,22,23,19)(17,24,25,20)(21,28,26,27)(2,4)(7,12)(9,11)(14,16)(19,22)(20,24)(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.