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)(27,32)(28,36)(29,34)(30,31)(33,38)(35,37)(39,40)(1,2,5,4)(3,7,8,6)(9,11)(10,15)(12,18)(13,17)(14,19)(16,22)(20,23)(21,24)(25,26)(27,32)(28,33)(29,34)(30,31)(35,39)(36,38)(37,40)(2,4)(6,7)(10,13)(15,17)(16,20)(22,23)(26,31)(29,32)(33,36)(37,39) involution — undirected(1,3)(2,6)(4,7)(5,8)(9,11)(10,15)(12,18)(13,17)(14,19)(16,22)(20,23)(21,24)(25,27,30,34)(26,32,31,29)(28,35,38,40)(33,39,36,37)(9,12,14,21)(10,16,13,20)(11,18,19,24)(15,22,17,23)(25,28,30,38)(26,33,31,36)(27,35,34,40)(29,37,32,39)(1,4,5,2)(3,7,8,6)(9,13,14,10)(11,17,19,15)(12,20,21,16)(18,23,24,22)(25,29,30,32)(26,34,31,27)(28,37,38,39)(33,40,36,35)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.