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