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