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