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)(15,22)(16,18)(20,27)(23,28)(24,26)(6,9)(7,11)(13,14)(15,23)(16,25)(17,19)(18,21)(20,24)(22,27)(26,28) involution — undirected(13,15,18,22,17,24,16,26)(14,20,21,28,19,23,25,27)(5,7,8,11)(6,10,9,12)(14,19)(20,23)(21,25)(27,28)(1,3,4,2)(6,9)(10,12)(13,16,17,18)(14,21,19,25)(15,22,24,26)(20,27,23,28)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.