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