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