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