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