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