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