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