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