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