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