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