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