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