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