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)(13,14,19,22)(15,20,25,23)(16,17,21,18)(24,26,28,27)(5,6)(7,10)(8,12)(9,11)(13,15,19,25)(14,20,22,23)(16,24,21,28)(17,26,18,27)(2,4)(13,16,19,21)(14,17,22,18)(15,23,25,20)(24,26,28,27)(5,7,9,8)(6,10,11,12)(13,16)(14,17)(15,24)(18,22)(19,21)(20,26)(23,27)(25,28)(5,8,9,7)(6,10,11,12)(13,17)(14,21)(15,25)(16,22)(18,19)(20,23)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.