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