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