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