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