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