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