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