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