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