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