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