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