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