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