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