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