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