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