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