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