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)(26,27)(29,37)(31,33)(35,40) 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)(25,26,30,27)(28,33,36,31)(29,32,37,34)(35,39,40,38)(2,6)(3,7)(10,15)(11,17)(16,21)(18,24)(25,26,30,27)(28,33,36,31)(29,32,37,34)(35,39,40,38)(3,7)(4,8)(9,12,14,20)(10,11,15,17)(13,22,23,19)(16,24,21,18)(25,27,30,26)(28,31,36,33)(29,32,37,34)(35,39,40,38)(1,3)(2,4)(5,7)(6,8)(9,11)(10,12)(13,18)(14,17)(15,20)(16,19)(21,22)(23,24)(25,28,30,36)(26,31,27,33)(29,35,37,40)(32,38,34,39)(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)(26,32)(27,34)(28,35)(30,37)(31,38)(33,39)(36,40)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.