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