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