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