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