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