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