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