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)(21,22,25,23)(24,27,28,26)(2,4)(6,8)(10,11)(13,14,17,19)(15,20,18,16)(21,23,25,22)(24,27,28,26)(1,2)(3,4)(7,12)(10,11)(13,15,17,18)(14,16,19,20)(5,7,9,12)(6,10,8,11)(13,16,17,20)(14,18,19,15)(21,24,25,28)(22,26,23,27)(5,8,9,6)(7,10,12,11)(13,14)(15,16)(17,19)(18,20)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.