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