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