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