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