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