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