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