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