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