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)(11,16)(12,15)(13,17)(14,18)(19,21)(20,23)(22,24)(26,30)(27,35)(28,37)(34,39) involution — undirected(3,8)(6,7)(9,11)(10,12)(13,19)(14,15)(16,18)(17,20)(21,24)(22,23)(25,26,31,30)(27,32,35,40)(28,33,37,38)(29,39,36,34)(1,3,5,8)(2,6,4,7)(9,12,14,16)(10,15,18,11)(13,21,22,20)(17,19,24,23)(25,27,31,35)(26,32,30,40)(28,29,37,36)(33,39,38,34)(3,8)(6,7)(9,12)(10,11)(13,20)(14,16)(15,18)(17,19)(21,22)(23,24)(25,28,31,37)(26,33,30,38)(27,36,35,29)(32,34,40,39)(1,3)(2,7)(4,6)(5,8)(9,11)(10,16)(12,18)(13,19)(14,15)(17,21)(20,24)(22,23)(25,29,31,36)(26,34,30,39)(27,28,35,37)(32,38,40,33)(1,4,5,2)(3,6,8,7)(9,13)(10,17)(11,19)(12,20)(14,22)(15,23)(16,21)(18,24)(25,30,31,26)(27,32,35,40)(28,38,37,33)(29,39,36,34)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.