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