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