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