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