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