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