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