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