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