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