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