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