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