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)(15,24,26,21)(16,18,23,25)(17,22,27,28)(6,10)(11,12)(13,15,19,26)(14,21,20,24)(16,22,23,28)(17,25,27,18)(1,2,3,4)(5,7,9,8)(6,11,10,12)(13,16)(14,18)(15,17)(19,23)(20,25)(21,28)(22,24)(26,27)(5,8,9,7)(6,12,10,11)(13,17,19,27)(14,22,20,28)(15,25,26,18)(16,21,23,24)(13,18,19,25)(14,23,20,16)(15,22,26,28)(17,24,27,21)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.