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