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