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