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)(15,23,24,19)(16,26,22,18)(20,27,28,25)(1,2,4,3)(5,6)(7,10)(8,9)(11,12)(13,15,17,24)(14,19,21,23)(16,20,22,28)(18,27,26,25)(6,9)(10,11)(13,16,18,14,17,22,26,21)(15,19,25,20,24,23,27,28)(5,7,8,12)(6,10,9,11)(13,15,18,25,17,24,26,27)(14,20,22,23,21,28,16,19)(1,3,4,2)(14,21)(16,22)(19,23)(20,28)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.