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