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