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