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