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