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