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