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