One vertex per element, one color per generator, with an edge from x to x·s.
(3,7)(5,8)(9,10,14,17)(11,18,20,24)(12,16,13,21)(15,22,23,19)(25,26)(27,33)(28,36)(29,32)(30,34)(31,37)(35,40)(38,39)(2,5)(3,7)(6,8)(9,11)(10,15)(12,19)(13,22)(14,20)(16,24)(17,23)(18,21)(28,37)(30,39)(31,36)(34,38) involution — undirected(1,2)(3,8)(4,6)(5,7)(9,12,14,13)(10,16,17,21)(11,19,20,22)(15,18,23,24)(25,27,29,35)(26,30,32,39)(28,38,37,34)(31,40,36,33)A 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.