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