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)(13,14,19,24,20,25,18,23)(15,26,27,22,28,16,17,21)(5,6)(7,11)(8,10)(9,12)(13,15,20,28)(14,21,25,22)(16,23,26,24)(17,18,27,19)(2,4)(5,7)(6,9)(8,12)(10,11)(13,16,20,26)(14,17,25,27)(15,23,28,24)(18,22,19,21)(7,12)(9,11)(13,17,19,15,20,27,18,28)(14,22,24,16,25,21,23,26)(6,10)(9,11)(13,18,20,19)(14,23,25,24)(15,27,28,17)(16,21,26,22)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.