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