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