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