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