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