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