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