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