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