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