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