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