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