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