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)(25,26,30,31)(27,29,33,37)(28,32,35,38)(34,36,39,40)(1,2,4,6)(3,5,8,7)(10,14)(15,17)(16,20)(22,23)(28,35)(32,38)(34,39)(36,40)(1,2)(3,5)(4,6)(7,8)(26,31)(27,33)(32,38)(34,39) involution — undirected(9,11)(10,15)(12,18)(13,19)(14,17)(16,22)(20,23)(21,24)(25,27)(26,29)(28,34)(30,33)(31,37)(32,36)(35,39)(38,40) 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)(25,28)(26,32)(27,34)(29,36)(30,35)(31,38)(33,39)(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)(26,27)(28,36)(30,37)(31,33)(32,34)(35,40)(38,39)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.