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