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