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