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