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