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