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