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