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