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