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