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