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