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