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