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)(14,15)(17,18)(20,23)(21,22)(24,25)(27,28) involution — undirected(1,2,3,4)(5,7)(6,9)(8,12)(10,11)(13,14,18,21,19,22,17,15)(16,24,28,23,26,20,27,25)(7,12)(9,10)(13,15,17,22,19,21,18,14)(16,25,27,20,26,23,28,24)(5,7)(6,10)(8,12)(9,11)(13,16,19,26)(14,20,22,24)(15,23,21,25)(17,27,18,28)(7,12)(9,10)(16,26)(20,24)(23,25)(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.