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