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