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