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