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