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