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