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