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