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