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