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