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