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