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