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