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