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