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