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