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