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)(13,14,19,23,18,24,17,22)(15,25,16,21,26,20,27,28)(5,7,10,6)(8,11,9,12)(13,15,17,27,18,26,19,16)(14,20,22,21,24,25,23,28)(2,4)(13,16,19,26,18,27,17,15)(14,21,23,20,24,28,22,25)(5,8,10,9)(6,11,7,12)(13,17,18,19)(14,22,24,23)(15,16,26,27)(20,28,25,21)(5,9,10,8)(6,11,7,12)(13,17,18,19)(14,23,24,22)(15,16,26,27)(20,21,25,28)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.