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