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