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