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