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