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