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