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