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