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