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