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