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