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