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