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