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