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