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