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