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