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