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