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