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