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)(11,17)(12,15)(13,16)(14,19)(18,24)(20,22)(21,23)(25,26,31,35)(27,33,29,32)(28,34,39,30)(36,37,38,40)(2,6)(3,8)(9,10,13,16)(11,14,19,17)(12,15,22,20)(18,23,21,24)(25,27,31,29)(26,32,35,33)(28,36,39,38)(30,37,34,40)(1,3)(2,4)(5,8)(6,7)(9,10,13,16)(11,14,19,17)(12,15,22,20)(18,23,21,24)(25,27,31,29)(26,33,35,32)(28,38,39,36)(30,37,34,40)(1,3)(2,4)(5,8)(6,7)(9,10)(11,14)(12,20)(13,16)(15,22)(17,19)(18,24)(21,23)(25,28,31,39)(26,34,35,30)(27,36,29,38)(32,40,33,37)(1,4)(2,3)(5,7)(6,8)(9,11)(10,14)(12,21)(13,19)(15,24)(16,17)(18,22)(20,23)(25,29,31,27)(26,32,35,33)(28,38,39,36)(30,37,34,40)(9,12,13,22)(10,15,16,20)(11,18,19,21)(14,23,17,24)(25,30,31,34)(26,28,35,39)(27,37,29,40)(32,36,33,38)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.