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