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