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