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