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