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