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