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