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