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