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