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