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