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