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