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