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