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