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