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