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