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