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