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