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