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