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)(13,14,18,19)(15,20,23,16)(17,25,26,21)(22,24,27,28)(5,7,9,8)(6,10,12,11)(13,15,18,23)(14,20,19,16)(17,24,26,28)(21,22,25,27)(2,4)(5,7,9,8)(6,11,12,10)(14,19)(15,16)(17,26)(20,23)(22,28)(24,27)(5,8,9,7)(6,10,12,11)(13,16)(14,15)(17,27)(18,20)(19,23)(21,24)(22,26)(25,28)(13,17,18,26)(14,21,19,25)(15,22,23,27)(16,24,20,28)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.