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