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