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