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