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