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