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