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