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