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