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