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