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