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