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