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