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)(15,19)(16,23)(17,21)(18,22)(20,25)(24,27)(26,28)(2,3)(6,10)(11,12)(13,15)(14,19)(16,23)(17,22)(18,21)(20,24)(25,27)(26,28) involution — undirected(1,2,4,3)(5,7,9,8)(6,11,10,12)(13,16,19,24,18,26,17,25)(14,20,21,28,22,27,15,23)(1,3,4,2)(5,8,9,7)(6,12,10,11)(13,14)(15,17)(16,20)(18,22)(19,21)(23,25)(24,28)(26,27)(13,17,18,19)(14,21,22,15)(16,24,26,25)(20,23,27,28)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.