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