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