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