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