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