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