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