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)(11,12)(13,17)(14,15)(16,20)(18,19)(21,22)(23,24)(25,26)(27,31)(28,37)(29,33)(30,34)(32,36)(35,40)(38,39)(3,7)(5,8)(10,15)(11,16)(17,24)(18,21)(25,27,30,35)(26,31,34,40)(28,29,36,39)(32,38,37,33)(1,2)(3,5)(4,6)(7,8)(10,15)(11,16)(17,24)(18,21)(27,35)(28,36)(31,40)(32,37) involution — undirected(1,3,4,7)(2,5,6,8)(9,11,14,16)(10,12,15,20)(13,21,23,18)(17,22,24,19)(25,28)(26,32)(27,29)(30,36)(31,38)(33,40)(34,37)(35,39)(1,2)(3,5)(4,6)(7,8)(9,12)(10,16)(11,15)(13,22)(14,20)(17,18)(19,23)(21,24)(25,26)(27,31)(28,32)(29,38)(30,34)(33,39)(35,40)(36,37) involution — undirected(9,13,14,23)(10,17,15,24)(11,18,16,21)(12,19,20,22)(25,29)(26,33)(27,36)(28,35)(30,39)(31,32)(34,38)(37,40)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.