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