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