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