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