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