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