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