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