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