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