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