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