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