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)(11,16)(12,22)(13,15)(14,18)(17,23)(19,24)(20,21)(25,26)(27,37)(28,40)(29,30)(31,34)(32,36)(33,39)(35,38)(1,3,5,8)(2,6,4,7)(9,11)(10,16)(12,14)(13,20)(15,21)(17,24)(18,22)(19,23)(25,27,32,39)(26,33,36,37)(28,38,31,30)(29,34,35,40)(9,12,15,23)(10,17,13,22)(11,19,21,14)(16,18,20,24)(25,28,32,31)(26,34,36,40)(27,38,39,30)(29,33,35,37)(9,12)(10,17)(11,14)(13,22)(15,23)(16,24)(18,20)(19,21)(25,29,32,35)(26,30,36,38)(27,34,39,40)(28,37,31,33)(1,2,5,4)(3,6,8,7)(9,13,15,10)(11,20,21,16)(12,22,23,17)(14,18,19,24)(25,30)(26,35)(27,28)(29,36)(31,39)(32,38)(33,40)(34,37)(1,4,5,2)(3,7,8,6)(9,14)(10,18)(11,12)(13,24)(15,19)(16,22)(17,20)(21,23)(25,31,32,28)(26,34,36,40)(27,30,39,38)(29,33,35,37)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.