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