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