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