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