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