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