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