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