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