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