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