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