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