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