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