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