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