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