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