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