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)(13,14)(15,24)(16,21)(17,22)(18,27)(19,23)(20,26)(25,28) involution — undirected(5,7)(6,9)(8,11)(10,12)(13,15)(14,20)(16,19)(17,26)(18,25)(21,22)(23,28)(24,27) involution — undirected(1,2,3,4)(6,10)(7,11)(13,16,19,15)(14,21,23,24)(17,26,18,25)(20,27,28,22)(7,11)(9,12)(13,17,19,18)(14,22,23,27)(15,25,16,26)(20,24,28,21)(13,17,19,18)(14,22,23,27)(15,26,16,25)(20,21,28,24)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.