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