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