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