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