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