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