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