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