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