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