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