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