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