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