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