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