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