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