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