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