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