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