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