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