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