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