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