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