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