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