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