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