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