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)(11,12)(13,16)(14,15)(17,18,21,20)(19,22,23,24)(25,26)(27,30)(28,31)(29,32)(33,35)(34,39)(36,38)(37,40)(9,11)(10,14)(12,16)(13,15)(19,23)(22,24)(25,26,29,32)(27,33,35,30)(28,31,38,36)(34,40,37,39)(9,12,13,14)(10,15,16,11)(17,19)(18,22)(20,24)(21,23)(25,26)(27,30)(28,36)(29,32)(31,38)(33,35)(34,40)(37,39)(1,2)(3,5)(4,6)(7,8)(9,11)(10,12)(13,15)(14,16)(25,27,29,35)(26,30,32,33)(28,37,38,34)(31,40,36,39)(1,3,4,7)(2,5,6,8)(9,12)(10,15)(11,16)(13,14)(17,20,21,18)(19,24,23,22)(25,28)(26,31)(27,34)(29,38)(30,39)(32,36)(33,40)(35,37)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.