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