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