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