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