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