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