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