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