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