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