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