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