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