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