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