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)(11,15)(12,20)(13,14)(16,22)(17,19)(18,24)(21,23)(25,26,30,33)(27,31,35,28)(29,32,38,40)(34,37,39,36)(3,7)(5,8)(9,10)(11,17)(12,20)(13,14)(15,19)(16,22)(18,23)(21,24)(25,27,30,35)(26,28,33,31)(29,34,38,39)(32,36,40,37)(1,2)(3,5)(4,6)(7,8)(10,14)(15,17)(16,20)(23,24)(25,28,30,31)(26,27,33,35)(29,37,38,36)(32,39,40,34)(1,3)(2,5)(4,7)(6,8)(9,11)(10,15)(12,21)(13,19)(14,17)(16,24)(18,22)(20,23)(25,26)(27,28)(29,32)(30,33)(31,35)(34,36)(37,39)(38,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,12)(10,16)(11,18)(13,22)(14,20)(15,23)(17,24)(19,21)(25,27)(26,31)(28,33)(29,34)(30,35)(32,37)(36,40)(38,39) involution — undirected(9,10)(11,15)(12,16)(13,14)(17,19)(18,23)(20,22)(21,24)(25,29,30,38)(26,32,33,40)(27,34,35,39)(28,36,31,37)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.