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