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