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