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