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