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