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