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