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