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