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