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