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