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