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