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