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