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