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