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