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)(11,13)(12,21)(14,22)(15,17)(16,20)(18,19)(23,24)(25,26,31,29)(27,32,37,35)(28,33,39,30)(34,36,38,40)(3,4)(7,8)(9,11,15,20)(10,16,17,13)(12,18,22,24)(14,19,21,23)(25,27)(26,32)(28,38)(29,35)(30,36)(31,37)(33,40)(34,39)(1,3)(2,7)(4,6)(5,8)(9,12,15,22)(10,14,17,21)(11,18,20,24)(13,23,16,19)(25,28,31,39)(26,33,29,30)(27,34,37,38)(32,36,35,40)(3,4)(7,8)(9,12)(10,14)(11,18)(13,23)(15,22)(16,19)(17,21)(20,24)(25,29,31,26)(27,35,37,32)(28,33,39,30)(34,36,38,40)(1,4,6,3)(2,7,5,8)(9,13,15,16)(10,11,17,20)(12,19,22,23)(14,24,21,18)(25,30,31,33)(26,28,29,39)(27,36,37,40)(32,38,35,34)(1,5,6,2)(3,7,4,8)(9,14)(10,12)(11,19)(13,24)(15,21)(16,18)(17,22)(20,23)(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.