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