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