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