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