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