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