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