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