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