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