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