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