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