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