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