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