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