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