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