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