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